Collaborative Research: Effects of Species on Forest Carbon Balances in Lowland Costa Rica

潮湿的热带森林的生物量和土壤中含有大量的碳，生产力也很高：因此，热带森林的生长、干扰和土地利用对大气中的二氧化碳水平有潜在的巨大影响。森林碳吸收和释放的精确建模对全球变化分析至关重要，但我们甚至不知道热带森林捕获或产生了多少二氧化碳。该项目将利用哥斯达黎加低地已有19年历史的复制种植园来评估对整个森林碳循环的物种水平控制。通过对4个物种的比较，将评估影响生态系统水平碳平衡的3个关键植物性状：1)碳利用效率（CUE）；2) CUE差异的植物部位（如叶片、木材）之间的分配；3)组织生化，影响碳循环速率。该项目更广泛的影响包括为本科生和研究生提供培训和国际经验。广泛使用的Century模型的进一步发展将在预测物种组成变化对生态系统碳平衡影响的能力方面取得重大进展。该研究地点的维护将为其他研究人员提供基础设施，并展示生态系统服务的恢复。研究结果将分发给科学界，也将分发给该地区的非政府组织和土地所有者。通过与仙童热带植物园的合作，开发一个用户友好的热带雨林模拟模型将为佛罗里达州迈阿密地区的29,500名K-12学生增加教育机会。

Moist tropical forests have huge amounts of carbon in their biomass and soils, and high rates of productivity: tropical forest growth, disturbance, and land use therefore have potentially large impacts on atmospheric CO2 levels. Accurate modeling of carbon uptake and release by forests is essential for global-change analyses, yet we do not even know how much CO2 tropical forests capture or produce. This project will make use of 19-yr-old replicated plantations in lowland Costa Rica to evaluate species-level controls over whole-forest carbon cycling. In comparisons among four species, three key plant traits that influence ecosystem-level carbon balance will be evaluated: 1) carbon use efficiency (CUE); 2) partitioning among plant parts that have differences in CUE (e.g., leaves, wood); and 3) tissue biochemistry, which influences carbon cycling rates. The broader impacts of this project include training and international experience for both undergraduate and graduate students. Further development of the widely used Century model will offer a major advance in the ability to predict the effects of shifts in species composition on ecosystem-level carbon balances. Maintenance of this research site will provide infrastructure for other researchers, and a demonstration of restoration of ecosystem services. Results will be disseminated to the scientific community, and also to NGO's and land-holders in the area. Development of a user-friendly rainforest simulation model will enhance education opportunities for 29,500 K-12 students in the Miami, FL area, though a partnership with the Fairchild Tropical Botanical Garden.